This invention relates to portable filtering apparatus and method for removing contaminants from used anti-freeze liquid by subjecting same to the action of serially arranged filters.
Heretofore filtering apparatus employed in an attempt to restore used anti-freeze liquid to a usable condition for automotive purposes either had limited effectiveness or was so complex as to be unjustifiably expensive. The prior art includes U.S. Pat. No. 5,091,081 which illustrates the use of serial filters including what is referred to as a pre-filter and following the pre-filter an ultrafiltration filter for use in filtering ethylene glycol anti-freeze liquid. A test kit contemplating the use of additives for restoring desirable characteristics to the coolant liquid is provided. The prior art is further illustrated and described in U.S. Pat. No. 5,174,902 which contemplates restoring anti-freeze coolant liquid to a usable state employing a particular cation exchanger. Conventional methods for purifying and recycling anti-freeze are also described including the use of diatomaceous earth as a filtering medium. The state of the art is further illustrated by U.S. Pat. Nos. 5,104,529, 5,407,564 and 5,395,514. Devices for collecting used oil are illustrated in U.S. Pat. Nos. 1,396,416 and 5,377,728.